It's madness: Researchers find that good sports games may cause more car accidents.

Don't get too mad this March: Engaging matchups in sports — such as between big college basketball rivals — may result in greater driving dangers for fans of the winning team.

In an analysis comparing traffic fatalities with exciting basketball and football games (both college and professional) in the last eight years, study researchers Stacy Wood of North Carolina State University and Melayne McInnes, of the University of South Carolina, discovered that, after a close game, fatal car crashes in the winning team's hometown were over 130 percent higher than when the win was a complete blowout.

The effect was found wherever the winning team's fans were when they were watching the game — both their home town and the game site.

Previous research showed an increase in traffic fatalities after the Super Bowl. Wood said she and McInnes were watching a boring University of North Carolina basketball game one day when they started to wonder if the excitement of the game played into the fatalities.

They came up with several competing hypotheses to test out: During boring games, people might drink more. Or, during close games, fans might come out of the game hyped up, which could contribute to dangerous driving.

Fatal fans

They found an actual link between close games and the number of traffic fatalities, but not the one they expected. It was not the losing fans, who might be driving away angry, who experienced more accidents; it was the winning team's home base.

The researchers (whose school is not involved in March Madness this year; its basketball team was not chosen for the NCAA tournament) hypothesize that sustained increased levels of the hormone testosterone might make winning fans aggressive. Research has shown that sports fans tend to have higher-than-normal testosterone levels during competitive games, but that when their team loses, the hormone quickly drops off. In addition to triggering aggressive driving, which is a major player in traffic fatalities, the testosterone might cause aggressive post-game drinking, the researchers speculate.

"Aggression in general could influence a lot of things other than just aggressive driving, including speeding and cutting into traffic. It could easily be other risky behaviors [linked to testosterone] as well," Wood told LiveScience. "Anything that can be done to help minimize that is important."

Not all biologists agree that testosterone causes aggression, though. "I'd say that several explanations are possible, and it isn't possible to tell them apart from the methods used," John Archer, of the University of Central Lancashire in England, told LiveScience in an e-mail. "The crucial question of whether such elevations in testosterone levels facilitate violent behavior — I'm not ruling it out, but it hasn't been established."

Keeping fans alive

Whether or not the increase in traffic deaths is due to testosterone, steps can be taken to minimize harm for the winning team's fans.

In places like South America and Europe, where soccer rivalries are legend, the winning fans are kept in the stadium for at least 45 minutes after the game. This precaution is meant to stop parking lot riots, Wood said, but it also may be useful for afterward — "anything that would keep people there for a little bit of time while that hormonal testosterone response would have a chance to diminish," said Wood.

As the 68-team NCAA tournament begins March 15, similar approaches could make future games safer in the United States. Keeping fans in the arena to get player autographs or hear the coach discuss the game, for instance, could help save lives, Wood said. Also, local traffic authorities and extra hospital staff could be kept on call.

Most of all, fans should be aware of how a game might alter their psyches. Taking time to calm down after a big win could save lives. "It’s a little bit of an ironic twist to having your team beaten in the last moment," Wood said, "but you probably have a safer drive home."